There was a time when the Chicago Bulls were considered the biggest threat to the Miami Heat’s dominance of the Eastern Conference. At least for the time being, those days are done.

When the Bulls were in position to challenge the Heat, Derrick Rose was at full strength and the Bulls’ reserves consisted of an entirely different cast. As much as things have changed in Chicago, they’ve stayed the same in Miami. LeBron James, Dwyane Wade and Chris Bosh have improved as a trio and so has the Heat as a team.

Rose is the only player not named LeBron to win MVP in the past five years, a clear indication of the level James has played at in recent years. He’s only getting better, and for Chicago, that’s bad news. Here are a few questions that are sure to determine just how badly things can go for the Bulls.

With Luol Deng ailing, who draws the task of guarding LeBron James?

In these playoffs, James has averaged 24.5 points, 7.8 rebounds and 6.8 assists and missed only 22 shots in a four-game sweep of the Milwaukee Bucks. Predictably, teams have trouble figuring out how to defend James.

The Bulls have been one of those teams. Each time Chicago faces off with the Miami Heat, Luol Deng’s number is called. He guards James about as well as one possibly could. And even with Deng doing an admirable job, James averaged 28.0 points, 8.0 rebounds and 4.5 assists in four games against the Bulls in 2012-13.

Deng will not travel with the Bulls to Miami when his team kicks off its Eastern Conference semifinals series against the Heat, and is listed as day-to-day and is unlikely to be at 100 percent if he does play.

If he doesn’t, the Bulls have a choice to make. The job of guarding James would probably fall to second-year man Jimmy Butler. He has proven himself to be a solid young defender on many occasions. James will present a new type of challenge, though.

Where does the Bulls’ overall health stand?

The Bulls have easily faced more injury than any other team in the NBA playoffs. From foot injuries to vomit-inducing flu symptoms, they’ve played through hell to reach the second round and will be rewarded with a date against the Miami Heat. How cruel.

As they were in a Game 7 win at Brooklyn, the Bulls will be shorthanded when their second-round series kicks off. Deng is recovering from complications to a spinal tap for viral meningitis, Kirk Hinrich can barely walk and Joakim Noah has performed through plantar fasciitis.

Chicago played through a drag of a seven-game series that ended Saturday, while Miami has been out and awaiting its next opponent since April 28. Health is always an issue because of the length of the NBA season. For the Bulls, their season has been defined by it, whether it was because of Rose’s torn ACL or this recent rash of injuries.

How will a series with the rugged Bulls affect the Heat’s title prospects?

When one thinks of the most physically gifted teams in the NBA, the Miami Heat immediately come to mind. James is an athlete unlike any the league has ever seen, Dwyane Wade is a physical guard and their supporting cast is flush with high-flyers.

The Bulls have traditionally lined up against the Heat without trouble in that department, matching length with length on the wings and pushing around the Heat’s small interior players.

The rugged nature of Chicago’s makeup could have been a problem in year’s past, but the Bulls are at a large talent disadvantage without Rose, their most physically gifted player.

If the skill to compete isn’t there, then the physical matchups don’t matter as much. The disparity between the ability of the Heat and Bulls will be clear to see in this matchup.

Prediction: Heat in 5

Miami has been the prohibitive favorites to win the 2012-13 NBA title since they took home the Larry O’Brien Trophy last year. Chicago, viewed as the toughest competition in years past, is depleted. The Heat, on the other hand, are at the height of their power. They’ll dispatch of the Bulls in five games.